Study: Standing babies stay steady when focused

October 3, 2012

Laura Claxton, a Purdue
assistant professor of health and kinesiology, interacts with 1-year-old Kenzie
Korchnak, after participating in a Purdue motor development study. Claxton's
recent findings show that babies learning to stand may look wobbly, but they
are really in more control than they appear, especially when they focus and
hold on to an object like a toy. Her work is published in the Journal of Experimental Child Psychology.
(Purdue University photo/Andrew Hancock)Download Photo

WEST LAFAYETTE, Ind. — Babies learning to stand may look
wobbly, but they are really in more control than they appear, especially when
they focus and hold on to an object like a toy, according to Purdue University
research.

"Babies learning to stand often sway and appear out
of control, but in this study, once we handed them a toy their standing posture
improved and they were more stable," said Laura Claxton, an assistant
professor of health and kinesiology who studies motor development in children. "Even
though babies are top heavy and their neuromuscular systems are immature, this
shows infants have more control when standing than many believe. Without the
toy to hold, they go right back to being unstable."

The findings also support previous research that swaying,
while it may look shaky, is another way babies explore the environment. Early
instability is functional, Claxton said. Body sway provides sensory information
that allows infants to learn how to appropriately control their body within
their environments. However, too much body sway would make it impossible for
the infants to focus on the toy, so Claxton believes that infants reduce their
amount of sway in order to better interact with the toy.

"These babies are shifting their postural strategies
in a manner that helps them accomplish their immediate goals of either
exploring the environment or engaging with a toy," Claxton said.
"They may look unsteady, but they are strategically adapting their
behavior."

The findings are published in the September issue of the Journal of Experimental Child Psychology.
The 16 babies, averaging 11 months old, in the study were independently
standing but not yet walking. Their standing time, movement and stability when
holding and not holding a toy was measured as they stood on a force plate.
Video recordings also were used to compare movements captured by the force
plate and the focus of the baby's attention.

"We are interested in whether this is a learned
behavior or innate," Claxton said.

It also could be that this posture control is learned when
infants learn to independently sit or that their development systems adapt so
quickly in just a few days of standing independently.

To answer these questions, long-term studies are needed to
follow babies from sitting to standing and to walking to understand the
continuum of motor development.

"Standing is not an easy task as babies learn to
balance with a small base of support in relationship to their bodies, and it
really says something about their development that the skill improves when they
multi-task," she said. "This work doesn't take place in a clinical
setting, but research about infant and child motor development can ultimately
help professionals monitor children's growth and help develop therapies and
assistance when there are problems."

Claxton also is comparing these results to how babies
alter posture and stability while fixating on pictures. She also will extend
this work to children who have difficulties with their balance, such as
children with cerebral palsy and Down syndrome.

The co-authors on this study are Dawn K. Melzer, an
assistant professor of psychology at Sacred Heart University; Joong Hyun Ryu,
Purdue graduate student in the Department of Health and Kinesiology; and
Jeffrey M. Haddad, Purdue associate professor of health and kinesiology.
Claxton's work is supported by Purdue's Department of Health and Kinesiology.

Note to
Journalists: Journalists interested in a copy of the journal article
can contact Amy Patterson Neubert, at Purdue News Service, 765-494-9723,
apatterson@purdue.edu

ABSTRACT

The control of posture
in newly standing infants is task dependent

Laura
J. Claxton, Dawn K. Melzer, Joong Hyun Ryu, Jeffrey M. Haddad

The postural sway
patterns of newly standing infants was compared under two conditions: standing
while holding a toy and standing while not holding a toy. Infants exhibited a
lower magnitude of postural sway and more complex sway patterns when holding
the toy. These changes suggest that infants adapt postural sway in a manner
that facilitates visually fixating on and stabilizing the toy in their hand.
When simply standing, infants exhibited postural sway patterns that appeared to
be more exploratory in nature. Exploratory sway patterns may allow infants to
learn the affordances of their new standing posture. These results demonstrate
that newly standing infants are capable of task-dependent postural control.